I have the same issues your talking about, especially your 3rd point.
Sometimes when dragging objects in my inventory, I have to do it twice. The first drag and drop on a quickslot, for example, the item isn't moved but if I drag and drop it again it works.
Also, in multiplayer if one person is sorting their inventory...all our inventories get sorted and this is a pain since I have to re-drag all my items back to where I want them to go.
